Control system



F. B. SCHRAMM CONTROL SYSTEM Filed 'May 131943 Jan. 3, 1950 Patented Jan. 3, 1950 STf-T EfSll PAT ENT O'FFI Ei heatin v`vsystems land i concerns: partie'u'l'ajriy"'iarrangenrientsfforicon;y trollingdistributioif of Vli'eal'afndother"forrnS"of energy? Y improved" energy "distribution" "'Systrni" of the control syst'rl Another obje'otof tri/invention is to provide' distzibutionjsystern vhaving independent tenr- 'I perature. or energy intensity. control in each of several .iiiferntffareas Halthough .-a com-mon energyV source is utilized. n

Stillanothenobjeetiof theinvention is to pro- Anotherfobject--is'to prov-ide a systemein which-- Fig. i2 is' a" iragmentafy'fschematic diagrjainl of Y a modi''eatin-in the arrangement of Fig. 1.-

Thosystinfiliustrated-fin Fig '1V comprises a sourcef'of lfieateneigylsuch as a: steam'lieating xl1' furnace, Ili for example, with a pluralityA of 'f energy'dissipatin-g elemen'ts'suoh" as radiators" |2,"|3 and '114, andl'supplly!-iinesfconneetingfthe neat source" n to 'th radiators' which 'mayV ytaker f'- f the'frinfi'ri thei'fspeio syster'nillustrated''f "ai steanifp'ipo 15 with branonilpipeg or connections if "55151 'and 128.111

device such as'a darnp pro'vid'e'dk and "Torf fconiolliig thbe 'interposed the?branch*lines 'or radiator' connctjion'sfflil ai'idll'respectivelyi For reason which fwillfbe y'explainedVl'ierenaiteiiautomati Like refereneeinuinerfals aref"utiiizodrthrough;v

radiators or energyfdissipatorsI may-'be operatedwith-normally-I openedfi valvesi to 'avoid interference witl'a- -iiuncontrolled floperatioirwin the f eventi* of failure :of power*Y or *of breakdowns in thefconewtroli systeme# tion'proceedsbf In Tnonandante\with*my*invention in itsf'pie-xv ferred formfI provide a'snitable sourcefof heat referred to for* co-nVeien-,s non, neutralpv-fienergy 'together' "with""radiato'ijs'` 'or 'the' :like 'for dissipating energy in the desired areas? An 'elec-f trially 'operatedoontrlle'r forV the heat supplyL i ll'andfadvantages''of 1' the' Systran wilt-Become apparent' as nie l(inscrip-iff i source "is provided; and therins'tatically 5 'coni' trolled valves are provided for independently A betton'u'ndorstanainei "of 'the'.

of the inventionl Whickrevbelievd to be rnovel independent i "control "f temperature 4in those" areas',"separate" therxnostatsj2li, 21 and 28 are provided, each "thefiostat'eiiig "located in one" of the 'spaees`-23f24 and 2'5, respectively, coritaining"alsocorrespondingradiators I2, [3 and For 'rendering' 'thejcontrone 1e rosponsiveto .tnetemperamres in ti'ie respective areas, 'a tripl' 'n' l corfductof'ntl systii's' provided comprising` three' conductors 31,*32 and' 33,5Whih -Inay'be and l" off conductors; respectively; For \con vertiente,'they Aon',ieutral-ajnd "-"oiA conductors 3|,'32 'and 33,7`and corresponding continuations thereof, are also identied bythe letters-R1, W and B, representing colors red, .whiteandibluep Whichlrnay be employed fgrthe insulationfof the y conductors for identification Vpurposesv in wiring the system.`

Thermostaticrelays' 34 -`and 35,-- responsive l to the-thermostats-M and25 respectively, are pro# n' vided for effeotingeontrobof Ytheidamperfregu-Y- appended-.l hereto.

In lthel drawing-Q p Figfl i`s a schematic diaflfram.includinganM electric circuit diaramA of one embodinentof my invention, and

andl 22. The damperfregu-latorl-S is shown as beingof theftype-having--a reversible motor-36 for operatingthe draft 31 andthe check damper-'- 38 of a-soli-d lfuelired Aboilerfir' a conventional f 55 lmanner. The form of the reversibleY motor 36 'Y illustrated involves an induction type rotor 39 cooperating with a pair of oppositely wound main stator windings 4| and 42, and a split phase or quadrature winding 43. For energizing the motor 36, an alternating current transformer 44 is provided having a secondary winding to which the split phase winding 43 is connected through a phase-splitting condenser 45 or the like and to which one or the other main windings 4| or 42 may be connected according to the direction in which the motor 36 is to rotate.

The damper regulator I9 is provided with control terminals 46, 41 and 48, respectively, corresponding to the control conductors 3|, 32 and 33 and which may be therefore identified as on, neutral and oir terminals respectively. The terminals 46 and 48 are connected to the free ends of motor field windings 4| and 42 respectively for driving the motor in the on and oil directions respectively and the terminal 41 is connected to the secondary winding of the transformer 44 for energizing one or the other of the windings 4| or 42 according to whether a contact is completed from the neutral terminal 41 to one or the other of the control terminals 46 and 48.

The thermostat 26 comprises a bimetallic blade 49 connected to a neutral thermostat terminal 5|, and a pair of stationary contacts, or on and of" terminals 52 and 53, with one or the other of which the moving blade 49 is adapted to make contact according to whether the temperature in the area 23 is below or above that which the thermostat 26 is designed to maintain.

The thermostats 21 and 28 may be similar in construction to the thermostat 26. As shown, they also have neutral, on and oil terminals 54, 55 and 56 and 51, 58 and 59, respectively. The thermostat relay 34 as shown comprises an operating winding 6| cooperating with an armature, not specifically illustrated, carrying three movable blades or contacts 62, 63 and 64 having a normal downward position. Cooperating with the blade 62 is a stationary normally-open holding contact 65; cooperating with the blade 63 is a stationary normally-closed valve-closing contact 66; and cooperating with the moving blade 64 are two stationary contacts, an upper or normally-openon-conductor contact 61 and a lower normally-closed neutral-conductor contact 68. Thus the blade 64 with its contacts 61 and 68 forms a double-throw or change-over contactor. For energizing the relay winding 6|, a -source of alternating current represented by a transformer 69 is provided and for permitting the relay 34 to be tripped vout by short-circuiting the winding 6 a series resistor 1| is provided.

The relay 34 has on, neutral and oil control terminals 12, 13 and 14, identified also by characteristic letters R, W and B, and connected respectively to corresponding terminals 55, 54 and 56 of the thermostat 21.

The thermostat relay 35, controlled by the thermostat 28, may be constructed and connected in a manner analogous to the relay 34.

The automatic heat control valve 2| is preferably of a normally open type in order that failure of the power supply, energizing the controller transformer 44 and the relay transformer 69, or failure of the control circuit 3|, 32, 33 will permit eiective manual operation of the heat source and uncontrolled or manually controlled operation of radiator |3, which may be provided with a manually controlled valve, not shown, for use in case of emergencies. Y -Y As illustrated, the valve 2| is of the electrically controlled type such as a valve of the type sold under the trade name of Thrustor, or an electromagnetic valve having a control winding 15 cooperating with an armature or plunger 16 which is normally biased in upwards position by a spring 11 bearing against a collar 18 on a valve stem 19 to which the plunger 16 is secured. In the drawing, the valve 2| is illustrated as being energized, with its plunger 16 drawn downward against the force of the spring 11 so as to seat the valve gate 8|. The valve 22 is constructed and connected similarly to the valve 2| and is shown in the drawing as de-energized so as to be unseated or open.

The on and off conductors 3| and 33 are connected to the on and off terminals 52 and 53 respectively of the thermostat 23. The neutral conductor 32 is connected to the neutral terminal 5| of the thermostat 26 through an extension of the neutral conductor represented by the lengths of conductors 82, 83 and 84 identified also by the letters RW which represent red and white, interlaced coloring in the conductor insulation, and return lengths of neutral conductors and 86, identied also by the letter W. 'Ihe normally closed contacts 64 and 68 of the relay 34 are interposed between the conductor lengths 32 and 82, and normally closed contacts 81 and 88 of the relay 35 are interposed between the conductor lengths 83 and 84. If the radiator 4 and the control elements 25 and 35 are to be the last ones in the system, a circuit between the conductor lengths 84 and 85 is completed between contacts of a switch 99 shown as closed, since no additional radiators and thermostats are shown. However, it will be understood that, if desired, the system may be continued as indicated beyond the right-hand end of the `drawing for including additional radiator control valves and thermostats and thermostat relays if desired. Likewise, if the thermostat 25 and relay 35 are not to be used, they may be cut out of the system by closing a switch 9| between the conductor lengths 82 and 85, in which case the switch 89 should be opened. The pipe |5 is shown with a broken end 92 to represent the possible extension of the system to additional radiators, but it will be understood that this end of the pipe will be capped if no additional radiators are to be used.

To provide for disconnecting the thermostat 26, when no temperature control in the space 23 is desired, the double-throw switch 93 is provided. The double-throw switch 93 comprises a movable blade or contact 94 and a pair of stationary contacts 95 and 96. Thecontacts 94 and 95 are closed when the thermostat 26 is in operation; and the contacts 94 and 96 are closed when the thermostat 26 is to be rendered inoperative. Thus, the contacts 94 and 95 normally complete the circuit between the neutral conductor lengths 85 and 86.

The stationary contact 96 of the switch 93 is connected to the off conductor 33.

The on conductor 3| has extensions 91 and 98 leading to the relays 34 and 35 respectively for rendering the controller |9 responsive to the thermostats 21 and 28, respectively. The on conductor extension 91 is connected to the upper contact 61 of the double-throw contactorincluding the blade 64 of the thermostat relay 34. Similarly, the ,on-conductor eiktension 98 is connected to a normallyopen upper contact 99 on the relay 35.

An automatic radiator control valve and a thermodena-f 23,?butzimay alsoibe omitted'if desi1-ed,=forrv the sake-uf fsimplicitya'ssumingrthe' space-23 is the one'mhichirnormally Lrunstthell-'coolest by rea-son of dimensionsiof the,spaceiheatedfexposure; for some and-$34 respectivelyimay. be provided: for' the space other reason. Consequently Whenever theltem-H peraturein the space23 fallsz belowithat foriwhich'.

penature--in the' 'spacesll24 ands2f5,1a contactfwill be closedfbetween .the onf-lianazfneutralfv terminalsI 1 5I and252 and the heati'controllerzIS will-be drivenV 'u in the ffonlp'osition -toY open thedraft 31 and 'close l, x

the-check-r-SB. HAssumingsthatthe temperature in the-space 24 is or has been'hig-her than required andithatlthe 'space 25 isi lowerl'thanrequired, the thermostat-S121 and28 take. up thepositions illusS-f More exactlythe thermostat 21 'is' shown in a f iloafting position; the neutral contact 54 making electrical'connection Withlneither the"on contactL55 Aari'orthe offf-contact5SH-It is assumed,

howevenlthatA-thecontacts-*54 and 55 have previously made electrical connection, short-circuit'.V

ing-ithe-control fw'inding v"Ii I tripping out the relay and'lcausin'gthe relay. contacts 62,'63 and 64 to fallito theflower position. if' Under these circum-` stan'ces,'=the'-valveclosing contacts 63 and 66 are closedffftherfeby -closing an electrical circuit from to thevalve control winding 15 a'ndmovin'gthe valveg'ate 8I downwardly into th-fseate'd-or closed :posi-tionas illustrated. Furthzmor'ey the relay contacts 64 and 68 of the relay -34 lare closed',l lea'vingfa` neutral conductor a current source IUI circuit between conductor lengths32 and82 andk allowing'theh'heatingl"system to be controlled by both thmOstats--ZG and 28.3

In the-fspace 215, in -whicn theltemperature is assumed lto be below' thatstatff28 isl s'et, the thermostat neutral andffon contacts 59 and 58 have been-'closed by the temperature condition 'and -the relay Winding4 I92 has accordingly" been energized closing holding conv tactsA I 031,?6pening` valveclosing contacts `|94 land moving the changeover contact or blade 31 to the" upvczard'pos'itionv making contactwith-the upper stationaryA contact 99."*'Owing to the vfact that the f valve-*closingfcontacts'"|04 have been'opened, the control-Winding of the valve 22 is deenergized and the' 'biasing s-pringIIlE2 moves ther valve 22 to the open-position causing heat energyto be supplied to theradiator or heat dissipating device I4.-

Owing to the `fact'that contact has been come" pletedibetweenschangeover contactorvcontacts 81 -l and99 Lof Vthe relay35,1the-neutral conductor lengthV 83 hasibeen disconnectedfrom the neutral-- conductor length84 d and'124 of control of the been-'connected to the on conductor extension A98 `causing fa circuit to be completed between the controller terminals 41 and into"A the on' thrmostati'ZG, alone, Yforms' a tem sponsivel-regulator in th the space 24,"a temperature regulator is formed by thlthermostatff-21 andthe'relay-SII taken together;

Although-in the-system illustrated and specifically idescribed' the extension conductors, Vsuch as thefcon'ductorsf191 and-'98 'connected to the normally` openzchangeover 'contacts 61 connected to the-'on. conductori 3 I to the/ofr'xconductor33, it will be understood thatimy-:invention lis. notnlinii-tedl-to that shown.-

46 causing it to move priving the thermostats 23 i heat controller I9. Fur" thermore-theneutral 'conductonlength 83 hasK or increasing heatV position. The

` peraturewee space 23;whereasin and 99, are I rather than .For example; if

"employing heat con lines, pipes for the .IMJ-The relay I09-fmay be sim Neverthelessvithelarrangementillustratedvis pref f erablefifsthe spacei23 tendsto be coolest-:1fwhereasf` the yreversef off conductor 33, couldbe fusedf Vwere-.the onerthatterrdewto be warmest.y `lor cute arrangement;iiii'vitl'i` connection-,to the i v.1

if thdspace 23 tin'grrouttV the thermostat-26 4the fcontactlS' of the i switch L93 lwould f be yconnect-'edi sto 3| :instead :of lthe. :conductor-33 ductors` 91 and n98 weres connectedfto thellcon-Lfi ductor-33u1 If desired, the `system yillustrated',;,may`.be uti-imV ya. h'eat .supply-:source: are; providing hot water; the tempera;k .w

located within thewaterfchamber of the. boilerr i II For `take li'thellforin of 'the stead of being located in the s In :'.thei'event lthatisnappace.23.1 action 'thermostatsof areused in the spaces v2II and-25, vthe'contaots 62,L65 r"aind'llli linay be omitt throwfcontactors 64 'andf81 damper-regulatorf-I9- Altho'ugl'i,` for? 'the'fsake 1v-of `convenience and simplicity, the system vfor-'di controlling the relative amounts distributed'fin '1f the variousspaees'haslbeendesoribedas a steam invention is notl li utilized'in connectio bution of energy or yhot lWaterI systems,

mlted thereto and may be maybe usedfin r:connection-fwith'fa system-'for '-1 distributing l some? other form of energy such as gle: stationaryv contact edand thefdouble'- serve to adaptsnap# action thermostats'to control of a three-contact 'l .type controller suche-as the i stributin'g energy and f-, 5

willIV be 'understood thatV -the ultra high frequency-or micro vWaveV energy in is transmitted through lcoaxial waveguide -type or the like and in which distribution-'of e movable danipers`v` gui' :le'pipes`.`vr 'It 'Will' he understood ythat-such movabledar-np valves 2-I and-*22 fr whollylor partially closing' ahollowep'ipe which the energy nergy fis controlled 'by f -or reec'tors within the `Waveers Awould `take'. ithe lplace of steam l1 iwave'fgui'de when. "waveenergy -pas-v 1 sage-throughlthepipewas`to be restricted or cutf oiTsfSuc-hr in the Vman-nerof the fvane" I-I3 'shot/nein the holgf55 of Patent 2,206,923 to Southworth."

amovabledamperlmay be arranged It mayl be desired that such-electric wave dis-1 of microwave energy if ng, in industrial procf a-systemcomprising a vblower led bya relay u III and normally openvicontactsfI-Hfr'l-energizingthe motor |08 wh'enwthe relay is energized; The contacts II2 correspondf-to the-"contacts"tilt, -I1 of thevrelay 34,`2ffor' example.*.Wh'e'n` the," heat controller IUT-""-Iilii's to be 'used linsteadfof `the controller I9, the Scontro] lsystemlconduetorsfl P32 and i 33 areconnectedl to controlttrinin'alsJ I3,` II4 and- Inicorresponding'f't'o the con` 7 ductors 12, I3 and 14 of the relay 34, for example. To permit alternatively using the heat controller |9 or the motor I'l, a triple-pole double-throw switch I6 may be provided.

If desired, the system illustrated in Fig. l may also be employed for independently controlling temperatures in various spaces such as the spaces 23, 24 and 2 5 and water temperature in a suitable reservoir |1 (Fig. 2). In this case, an additional relay-controlled valve and corresponding parts are provided such as an Aquastat ||8 corresponding to the thermostat 21, a relay I9 controlled by the Aquastat ||8 and corresponding to the relay 34, and an electrically controlled valve |2| corresponding to the valve 2| and controlled by the relay I I9. Such a system may be employed in connection with a boiler II having a heat exchanger |22 of conventional type, connected by supply and return pipes |23 and |24, respectively, to the storage tank The control valve |2| is interposed in one of the pipe connections |23 or |24. The arrangement of Fig. 2 is represented only schematically but it will be understood that the connections and arrangements of the elements ||8, ||9 and |2| are similar to those of the corresponding elements utilized for controlling the heat supply to the radiator I3, for example.

I have herein shown and particularly described certain embodiments of my invention and certain methods of operation embraced therein for the purpose of explaining its principle of operation and showing its application but it will be obvious to those skilled in the art that many modifications and variations are possible and I am, therefore, to cover all such modications and variations as fall within the scope of my invention which is deiined in the appended claims.

What is claimed is:

1. A heating system comprising a heat energy source, a plurality of radiators in different spaces to be heated, a distribution line connecting said radiators to said heat source, a plurality of thermostats, each in one of said spaces, an electrically controlled normally-open valve between said distribution line and each radiator except the rst, an electric controller for the said heat source, a triple conductor control-circuit system running from said controller to said thermostats, and a thermostat relay for each thermostat except the first, each thermostat being of the double-throw type having on and off terminals and a temperature-responsive moving blade connected to a neutral terminal, and the controller being of the three-terminal reversing type with on, ofL and neutral terminals, increasing heat when the on and neutral terminals are connected and decreasing heat when the oi and neutral terminals are connected, the control circuit system including on, off and neutral conductors connected respectively to the on, off and neutral controller terminals, the rst thermostat having its on and oi terminals connected to the on and ofi conductors respectively and its neutral terminal in circuit with the neutral conductor, each thermostat relay including on, off and neutral individual control terminals, a double throw neutral-conductor contactor, and a normally-closed valve-closing contactor, each thermostat except the first having its on, off and neutral terminals connected to corresponding terminals of a corresponding relay, each relay double-throw contactor comprising normally closed contacts in series with the neutral conductor between the heat controller andthe rst thermostat and normally open contacts between said neutral conductor and the on conductor, each valve having a control winding in circuit with the valve-closing contactor of the relay connected to the thermostat within the same space as the radiator controller by such valve.

2. A heating system comprising a heat energy source, a plurality of radiators in different spaces to be heated, a distribution line connecting said radiators to said heat source, a plurality of thermostats, each in one of said spaces, a plurality of electrically controlled normally open valves each between said distribution line and a radiator, an electric controller for the said heat source, a. triple conductor control circuit system running from said controller to said thermostats, and a thermostat relay for each valve, each thermostat being of the double throw type having on and oir terminals and a temperature responsive moving blade connected to a neutral terminal, and the controller being of the three-terminal reversing type with on, om and neutral terminals, increasing heat when the on and neutral terminals are connected and decreasing heat when the oi and neutral terminals are connected, the control circuit system including on, oif and neutral conductors connected to corresponding controller terminals, each thermostat relay including on, off and neutral individual control terminals, a double-throw neutral-conductor contactor, and a normally-closed valve-closing contactor, each relay having its on, "off and neutral control terminals connected to corresponding terminals of a corresponding thermostat, each relay double-throw contactor comprising normally closed contacts in series with the neutral conductor between the heat controller and the first thermostat and normally open contacts between said neutra conductor and the on conductor, each valve having a control winding in circuit with the valve-closing contactor of tne relay connected to the thermostat within the same space as the radiator controlled by such valve.

3. A heating system comprising a vheat energy source, rst and second radiators in diiierent spaces to be heated with connections to said heat source, first and second thermostats each within one of said spaces, an electrically controlled normally-open valve in the connection to said second radiator, an electric controller for the said heat source, a control circuit system running from said controller to said thermostats, and a thermostat relay for said second thermostat, said thermostats being of the double throw type having on" and oi terminals and a temperatureresponsive moving blade with a neutral terminal connected thereto, and the controller being of the three-terminal reversing type with on,

off and neutral terminals, increasing heat when the on and neutral terminals are connected and decreasing heat when the ofi and neutral terminals are connected, the control circuit system including on, off and neutral conductors connected between the on, off and neutral terminals respectively of said controller and said first thermostat, the relay having on, off and neutral control terminals connected to respective corresponding terminals of said secthe neutral conductor and normally open conond thermostat, a double-throw neutral-conductor contactor, and a normally-closed valve-closing contactor, said double-throw contactor comprising normally closed contacts in series with tacts between 4saidneutral conductor and said monftco'nductor, the valve having-a control windatyandgbeing ofthe. type increasing :heat vwhen.

:.-f'fdecreasing heat when terminals .are closedon, olif and` neutral ing -i-n circuit with the valve-'closing contactor.

4. 1A heatingsystemcomprising la heat energy i. source-'a thermostatiorcontrolling the same of the double-thrown type` having --on and off terminals-` and atemperature-responsive blade with a neutral terminal connected thereto, a radiator in a-space' to beV heated with a con- `AnectionI to said--heatsource, a second rthermo-v the onandneutral, terminals are closed` and .the `foi and neutral f.; conductorsconnected between the on, off and Q neutral terminals, respectively, 2: and.; said; first thermostanandi :means controlled of the controller.

--. by said second. thermostatincluding a ,.-double thro-w neutral-conductor contactor and a normally-closed valve-closing contactor, said doublethrow contactor comprising normally closed contacts in series with the neutral conductor and normally open contacts between said neutral conductor and said on conductor, the valve having a control winding in circuit with the valve-closing contacts.

5. A heating systemcomprising a heat energy source of the controlled combustion type, a thermostat for controlling the same of the doublethrow type having on and off terminals and a temperature-responsive blade with a neutral terminal connected thereto, a radiator in a space to be heated with a connection to said heat source, a second thermostat in said space, alternative electric combustion controllers for said heat source, one being of the damper-regulator type, and each having on, off :and neutral terminals and being of the type increasing heat when the "on and neutral terminals are closed and decreasing heat when the off and neutral terminals are closed, a three-pole double-throw transfer switch having corresponding stationary contacts connected to corresponding terminals of said controllers and three movable contacts, each with a terminal, designated as an on, 01T or neutral terminal, on, off and neutral conductors connected between the on, 01T and neutral terminals, respectively, of the transfer switch and said iirst thermostat, and a double-throw neutral-conductor contactor controlled by said second thermostat, said doublethrow contactor comprising normally closed contacts in series with the neutral conductor and normally open contacts between said neutral conductor and said on conductor.

6. A heating system comprising a heat energy source, a thermostat for controlling the same of the double-throw type having on and off terminals and a temperature-responsive blade with a neutral terminal connected thereto, a radiator in a space to be heated with a connection to said heat source, a second thermostat in said space, an electrically controlled valve in the connection to the radiator, an electric controller for said heat source having on, on and neutral terminals and being of the type increasing heat when the on and neutral terminals are connected and decreasing heat when the ofi and neutral conductors are connected, on, oil and neutral conductors between the on, oi and neutral terminals, respectively, of the con- .lil

-tr-oller and said-'nrst-thermostah .and-means con- ,trolledv by said second thermostatincluding a fdouble -thro-w.neutral-conductor contactorand a valve-operatingcontactomsaid `double-throw conytactor Lcomprisingnormallyclosed contacts in 4--series-with thee-neutral` conductor-and normally Hopent-contacts;between said neutral conductor and said on conducton-thevalvehaving acontrol winding in--circuit 'Withfsaid valve-operating contactor.

7. AA triple-conductorcontrol system for use in controlling alconditionby-whichever one of -a plu- -f-ralit-y of yregulators is actuated comprising on, -oiTv and` neutral conductors, a plurality of `threeterminal'regulators in succession, connected to said-conductors, a-control' transfer contactor associated with each regulator for cuttingv out a succeeding one of said regulators upon actuation of vvthe regulator with which --thecontroltransf er contactor'is associated, each 'such contactor corn- A prising av double-throw switchl with afpairof normally closed contacts in vseries 'with'said `neutra] conductor, and la third contact connected to one of the other conductors and adapted to make contact with one of the other contacts when a regulator is to be cut out, and a switch for bypassing said normally closed contacts of any contactor when succeeding regulators :and contactors are toI be cut out.

8. An energy distribution system comprising an energy source, rst and second energy consumers located in diierent spaces to be supplied with energy and having connections to said source, iirst and second intensity-responsive devices, each in one of said spaces, an electrically controlled normally-open valve in the connection to said second energy consumer, an electric controller for the said source, a control circuit system running from said controller to said rst intensity-responsive device, and a relay for said second intensity-responsive device, said intensity-responsive devices being of the double-throw type having on and oiT terminals and an intensityresponsive moving element with a neutral terminal connected thereto, and the controller being of the three-terminal reversing type with on, 01T and neutral terminals, increasing energy supply when the on and neutral terminals are connected and decreasing energy supply when the off and neutral terminals are connected, the control circuit system including on, off and neutral conductors connected between the on, 01T and "neutral terminals respectively of said controller and said rst intensity-responsive device, the relay having 011, oir and neutral control terminals connected to respective corresponding terminals of said second intensity-responsive device, a double-throw neutral-conductor contactor, and a normally-closed valve-closing contacto-r, said double-throw neutral-conductor contactor comprising normally closed contacts in series with the neutral conductor and normally open contacts between said neutral conductor and said on conductor, the valve having a control winding in circuit with the valve-closing contactor.

9. An energy distribution system comprising an energy source, rst and second energy consumers located in different spaces to be supplied with energy and having connections to said source, rst and second intensity-responsive devices each in one of said spaces, an electrically controlled valve in the connection to said second energy consumer, an electric controller for the said source, a control circuit system running from nected and decreasing energy` supply when the off and neutral terminals are connected, the control circuit system including on, off and neutral conductors connected between the on, oi and neutral terminals respectively of said controller and said first intensity-responsive device, the relay having on, oi and neutral control terminals connected to respective corresponding terminals of said second intensityresponsive device, a double-throw neutral-conductor contactor, and a valve-operating contactor, said double-throw contacter comprising nor- 12 mally-open and normally-closed contacts, one set of contacts being in series with the "neutral conductor and the other set being between said "neutraP conductor and said on conductor, the valve lhaving a control winding in circuit with the valve-operating contacter.

FREDERIC B. SCHRAMM.

REFERENCES CITED The following references are of record in the me of this patent:

UNITED STATES PATENTS Number Name Date 1,167,815 Gold Jan. 11, 1916 2,013,450 Stark Sept. 3, 1935 2,067,426 Stuart Jan. 12, 1937 2,119,153 Dallenbach May 31, 1938 2,153,382 Martin Apr. 4, 1939 2,244,631 INessell June 3, 1941 2,304,124 Sampsel Dec. 8, 1942 2,310,745 Parks et al Feb. 9, 1943 

